


Secrets Of The Sea

by becsbunker



Series: Mermaid/Merman AU oneshots [1]
Category: Supernatural
Genre: Angst, Character Death, F/M, Fluff, Magic, Smut, Witches, mermaid au
Language: English
Status: In-Progress
Published: 2018-12-13
Updated: 2018-12-13
Packaged: 2019-09-17 12:32:19
Rating: Mature
Warnings: Major Character Death
Chapters: 2
Words: 4,976
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16974660
Author URL: https://archiveofourown.org/users/becsbunker/pseuds/becsbunker
Summary: {Sidenote: mare maleficus means sea witch in latin.}





	1. Secrets Of The Sea

 

**Summary: Life under the sea isn’t always easy, and things take a whole new turn when you venture through the forbidden bunker.**

> **Pairing: Merman!Dean x Mermaid!Reader**
> 
> **Warnings: sea witches, mentions of character death(s), threat, angst, fluff**

[Originally posted by holographicglittercocaine](https://tmblr.co/ZDPnAi2AFalif)

[Originally posted by shirtlesssammy](https://tmblr.co/ZG9WDj2ZVd17E)

> _**written for[@siren-kitten-his](https://tmblr.co/mmEuSAgsLeSvMWBWpUf8Hzg) mermaid challenge with the prompt ‘in exile’ and also [@thing-you-do-with-that-thing](https://tmblr.co/mCkeWlUxrGTcuvucz7e4MjQ) heat of summer challenge with the prompt bolded in the fic.** _

* * *

Your father always told you to stay away from the bunker, the part of the sea where the caves outlined the barrier between land and the waters.

Stories were told of mermaids and sea creatures that ventured out toward the bunker. They would tell how the monster that lived there made sure they never returned. That he was a vicious beast outcast by the sea witches to keep the seas safe.

You never understood how the stories came to pass if they were no survivors living to tell the tale. Sea witches were hardly the most reliable of sources to begin with.

“I’ll be back soon, papa. I’m going to check on the new dolphin pod,” you said, earning a short nod from you father who was about to start a meeting with the council of your mermaid pod.

You swam with quick strokes through the depths of the water, navigating your way towards the dolphin pod with expertise. There was always such a freedom you felt when you swam around your home. You came to recognisd the various creatures that lived and swam in the same ocean, each of them different and beautiful.

Once you found the new dolphin pod you’d been helping, you swam with them for the next few miles, smiling at the way the youngest dolphins raced beside you.

They were growing so fast, learning so quick. They were by far some of the most intelligent animals under the sea.

You stopped suddenly in your tracks as you saw the entrance of the caves a few metres before you.

You’d never ventured so far out. Never seen the bunker up close.

With the underwater caves front of you, it didn’t look all that threatening. There was something almost delicate looking about the natural structure, the gaps that lead through to darkness intrigued you.

The warning calls of the dolphins caught your attention and as you spun round to check on them, you saw a large great white shark heading straight in your direction.

Panic fled through ever fibre of your body as you quickly raced through the water away from the sharp, hungry teeth and mouth of the shark.

The faster you swam, the quicker your arms and tail began to ache. As hard as you tried to fight the exhaustion, your adrenaline was soon becoming clouded by fear. You didn’t know how much longer you could go on for.

A loud yelp rang out around you and you peeked over your shoulder quick enough to see the shark impaled by a silver spear, very similar to the ones the guardians of pod kept back home, as it fell into the dark depths of the sea.

You slowed to a stop, eyes frantically searching for where the spear had been thrown from. All you could see in the distance was a retreating figure swimming back into the entrance of the cave.

The bunker.

“Wait- please!” you called, still a little breathless from your ordeal as you cautiously swam toward the mouth of the cave.

“He-hello?” you paused, seeing the back of the figure.

You were surprised by the fact the figure was a merman. Not a monster. Not a deadly creature. A merman.

When he turned to look at you fully, you could’ve sworn your breath caught in your throat.

He had a well sculpted torso, his skin peppered in freckles with the greenest eyes you’d ever seen. His tail was a royal blue in colour, shimmering softly in the reflection of the water.

This mysterious merman was one of the most stunning beings you’d ever set eyes on.

“What are you doing through here? Get out!” He yelled, approaching you with a warning look in his eyes.

“I just- I wanted to thank you for saving me back there,” you defended, surprised by how on edge he was.

His jaw visibly clenched before he let out a sigh, “you shouldn’t be out here.”

You frowned. “Because of the monster who lives in this bunker? Because I don’t see a monster. All I see is you.”

The merman’s mouth fell open slightly.

He trailed much closer to you, his eyes searching your e/c ones and you felt your blood pump faster at the new proximity between you.

“How do you know I’m not a monster?”

“Because you saved me,” you answered. “I don’t believe a monster would do that. Especially one’s that hate mermaids.”

A hint of a smile tugged at his lips and you found yourself staring at his face, totally enchanted.

“I don’t hate mermaids, sweetheart,” he said, pulling you from your daze. “I hate sea witches. They’re the reason I’m in exile out here.”

“What happened?” You asked, honestly curious about how this handsome, smart merman ended up in exile because of witches.

“I made a deal with them to save my younger brother, Sam,” he told you, his eyes looking down, avoiding your gaze.

“Sammy is your brother?” Your eyes widened in realisation.

Sam was one of the guardians of your pod and your best friend. He told you once he had an older brother who he thought died after a shark attack. It’s the first and only time he spoke to you about Dean, the memory obviously too painful for him to go over.

“You- you’re Dean. You were part of of our pod. Sam thinks you died after a shark attack,” you said, a sadness in your voice.

Dean visibly tensed and he turned away and swam further through the caves, you following close on his tail.

“Dean! You need to come home!”

“No, I can’t!” He snapped, stopping chest to chest to you. “If I go back, Sammy dies. That’s the deal I made with the witches. I wasn’t the one who got attacked by the shark, Sam was.”

Your heart sank in your chest and you let out a shaky breath. “Did he- did he die?”

Dean’s eyes became glossed over at your question, tears pricking the corner of his eyes as he nodded.

You threw your arms around him, pulling your body in close and hugging him.

“I’m so sorry,” you whispered against his ear, voice weak with your own emotion.

You couldn’t begin to imagine the pain Dean had gone through. The sacrifice he had made to save his brother.

Dean let out a long breath at the unfamiliar comfort before wrapping his arms around you, grateful for your presence.

You weren’t sure how long you both stayed in each others hold, just seamlessly floating in the safe confine of the bunker. There was something that felt so natural and right about being close to him. You wanted to do everything you could to help him. To reunite him with his brother.

Dean’s eyes searched yours when you pulled away, a sense of loss over his face.

“There’s something I need to do. I’ll come back, I promise,” you said, giving him a reassuring smile before heading back out of the caves.

You swam as fast as you could back home. Thankfully when you got back to the pod, the meeting was still going on so it gave you the chance to sneak into the tomb to retrieve your grandfather’s trident.

It contained magical properties, ones that you knew could help both Sam and Dean.

“Y/N, what are you doing?”

You spun round at the familiar voice, coming face to face with Sam who had a concerned look across his face at the sight of you there with the powerful trident in your hands.

“I need to take it for a moment. I’ll bring it back,” you reasoned, but Sam wasn’t having any of it.

“You can’t leave with that and you know it. What’s going on?” He asked, arms folded across his sculpted chest.

“I need it to help your brother, Sammy. He’s alive. He made a deal with witches to save your life after the shark attack,” you explained. “Dean’s been living out at the bunker ever since.”

Sam’s eyes widened as he swam closer to you, his heart beating fast in his chest.

“He’s- he’s alive?” He stammered, eyes welling with tears.

You nodded, placing a hand on your friends arm comfortingly.

“I have an idea to break his deal, but I might need your help.”

~~~~~~~~

Dean could hear you arrive back at the bunker, a big part of him relieved you’d actually returned.

If he was you, he’d swim away from here and never come back.

“Did you go and get some oysters or some-” Dean’s sentence broke off as he turned around to see you, the trident and his brother.

“Sammy,” he breathed, not hesitating as Sam, who had grown up into this great hulk of a merman, came at him and hugged him.

“I can’t believe your alive,” Sam said shakily as he pulled away, still in disbelief. “And you’ve been in here all this time. You shouldn’t have made that deal, Dean.”

“I had to. I promised I’d always look after my pain in the ass little brother. I don’t break promises,” Dean said, barely holding back the emotion in his own voice.

Sam gave a small nod. “I know. You’re lucky Y/N found you. No one else is crazy enough to come in here.”

“Hey! I heard that,” you scolded.

“Yeah, you were meant to,” Sam smiled over his shoulder at you.

Frowning, Dean swam a little closer to you and you felt this undeniable warmth at seeing him again.

“Not for nothing, sweetheart, but I’m pretty sure stealing the trident is some form of treason,” he gestured to the gleaming object in your hand, “what are you doing with that thing?”

“I’m going to turn you and Sammy into humans.”

Dean scoffed a laugh. “You’re joking right?”

When your expression didn’t falter, he turned to look at Sam.

“Please tell me she’s joking.”

Sam shook his head. “It’s the only plan we’ve got that might actually work. Sea witches can’t set foot on land. It’s the best chance we’ve got,” he reasoned.

Dean furrowed his brows. “But what about the pod? Sammy, that’s your home.”

“Dean, you’re my brother. There’s nothing I wouldn’t do for you,” Sam said sincerely. “I’ve just got you back. I can’t lose you again.”

Dean shook his head. “I can’t let you do this, man.”

“You didn’t mention how stubborn he was,” you piped in, earning an unamused look from Dean and a smile from Sam.

“Look, if we don’t do this soon, the guardians are going to be looking for the trident. I’d rather get this done before my Father decides to turn me into shark bait,” you told Dean.

“Then come with us.”

Your mouth fell open at Dean’s reply.

For a split second, you could actually imagine life on land with Sam, with Dean. Sam was your best friend and Dean, well, he just seemed to have stolen your heart.

“I-I can’t,” you murmured, a pained expression across your face.

“Y/N, please.”

Dean went to approach you, but before he could reach you, you raised the trident, a glow of gold sweeping across the bunker. In a blink of an eye, both Sam and Dean were gone.

**_3 months later_ **

The brothers were sat on the beach, Sam with a book in his lap and Dean looking absent-mindedly out into the sea. It was in the heat of summer, the sun shimmering it’s reflection against the water and the warmth fanning against Dean’s skin.

Their three months on land had definitely been an experience that took a lot of adjusting. Everything was so different out of the water. Firstly, they had to learn how to use legs rather than a tail. There were no sea creatures that wanted to eat them, or witches waiting to wreak havoc (that they knew of, yet)

It was a simpler life. But there still felt like there was something missing. 

Someone missing.

“You’re thinking about Y/N, aren’t you?” Sam looked up from his book, following Dean’s gaze toward the water.

Gentle waves were brushing against the sand, the sea of blue running back as far as the eye could see. It all looked so calm and serene out there.

“Do you think she’s alright? I mean, after stealing the trident and turning two merman into humans,

It’s not exactly legal,” Dean said, anxiously playing with his hands at the thought.

“She’s stronger than she looks, and smart as hell. I’m sure she’s fine down there,” Sam placed a hand on his brothers shoulder, “and I miss her, too.”

Dean swallowed down the tears as he got to his feet.

“I’m going to get some ice cream. You want anything?” he offered.

“Just a water, thanks.”

Dean huffed a laugh, shaking his head. “Wow, living the wildlife there, bro.”

Sam scowled at him. “Shut up,” he retorted, going back to his book.

While Dean was walking to the small cafe a little further down the beach, he could’ve sworn he saw the back of a figure that looked identical to you. Except this woman had legs, not a tail.

Shaking the thought away, he made his way to the line of people waiting to order at the cafe.

His mind was a million miles away before a familiar female voice spoke from behind him,  **“I never thought I’d say this, but put on a shirt before you burn.”**

Dean had never moved so quick. As he turned to face you, he became completely star struck at the sight of you. You were now human, wearing a two piece bikini and a hat.

Before you had a chance to say anything else, Dean had closed the space between you, his face mere inches apart from your own as he cupped your face in his hands.

“I didn’t think I’d ever see you again,” he spoke softly, his eyes searching your face.

“Me either,” you replied, gently caressing his face, memorising every freckle, the light stubble now over his face, those stunning green eyes.

Dean didn’t hesitate any longer, pressing his lips to yours in a tentative kiss. His lips were soft and warm against yours. You could feel sparks igniting through your veins at this brand new feeling, from this connection between the two of you.

You’d never been kissed before and you never wanted this one to end.

“Hey! Quit holding up the line!” A woman interrupted, causing you and Dean to reluctantly pull a part.

You glared at the woman who had just ruined the perfectly good moment. That, and the way she was eyeing up Dean like he was her next meal did not sit well with you.

“Here’s some friendly advice, don’t go too far out in the water,” you retorted, causing Dean to drag you away from the crowds before the woman could say anything else.

“Relax, sweetheart. She’s just a human,” he chuckled.

“I hope they’re not all like that,” you huffed, letting Dean hold his arm around you.

“Why, are you planning on sticking around?” He asked, ever hopeful.

You smiled at him, revealing the necklace around your neck with a small trinket of the trident on it, “I’ve decided to try out life as a human. My father got sick of me moping around. I missed Sammy. and I missed you, a lot.”

Dean’s face lit up with a smile and he pressed a kiss to the top of your head.

“A new life on land, huh? You’ve got some things to learn,” he teased.

“Figured I’ve got two good teachers. One of them even knows how to fend off sharks,” you smirked. “Very heroic.”

“It was, wasn’t it? How will you ever repay me?” He grinned.

You paused, stopping in front of him with your hands on his shoulders.

“Apparently there’s a few things humans can do that mermaids can’t. Guess we can figure those things out over time,” you winked before rushing across the sand to see Sammy.


	2. Heart In The Ocean

 

>  

**Summary: You’re a Mermaid whose returned to land looking for a weapon to take out your kin after they recently killed half a dozen innocent men out at sea. But what happens when you meet the Winchesters who are after the same thing?**

**Characters: Dean x Mermaid!Reader, Sam Winchester**

**Warnings: language, angst, implied smut, character death(s), more angst**

> __**‘Who knows how long I’ve been awake now?  
>  The shadows on my wall don’t sleep  
> They keep calling me, beckoning,**   
> 

You’d never felt the way about anyone like you had about Dean Winchester.   **  
**

You were investigating a case where a group of men had hired out a boat from the docks, and only one came back alive. That’s when you first met Sam and Dean Winchester. 

The other five men on the boat were taken over board by what the man described as the most beautiful women he’d ever seen, and that they had scaled tails and fins. You knew it was probably the work of your mermaid kin. But, you had to make sure it was really them who’d been doing the killing, after all there were many more monsters who swam beneath the sea. You were thankful your Father had been human, it seemingly gave you a lot more control on the urge to kill while you were in your Mermaid form.    

You were completely lost in his jade green eyes, even when he was quizzing you on who you were and why you were there. 

How could a mere human practically be made in the image of gods?

* * *

You told both him and his brother that you were investigating the deaths, which wasn’t a total lie. You explained that you were a mythology professor at the local university and you were interested in the suspicious deaths that seemed like the work of mermaids. You could tell they were both pretty unsure over the whole mermaid theory at first, but it didn’t last long. You were sure these two men had faced other monsters in their time, and that was even before they admitted to being hunters.

Why did he have to be a hunter? The one man you’d ever met on land who you fell for and he just happens to be the same man who could kill you in an instant. 

Typical.

You had to admit, meeting Sam and Dean kind of gave you second thoughts about removing the silver, magical necklace around your neck and returning to your true form in the sea. But, then you remembered that your relatives were currently killing innocent men by drowning them and dragging them to the dark depths of the ocean. You had to stop them, before it was too late. **  
**

“So, this will kill them?” Dean queried as the three of you reached the glass cabinet in the museum with a trident inside.

You nodded, holding you hand against the glass. The gold the trident was made from was toxic to mermaids, all mermaids.

Dean broke the glass cabinet without a second thought and grabbed the trident before the three of you made a quick run for it back to the car, the alarms of the museum blaring as you left.

> _**‘Who knows what’s right? The lines keep getting thinner  
>  My age has never made me wise  
> But I keep pushing on and on and on and on,** _

“You sure you don’t want a beer?” Dean offered as the three of you sat in the motel room, the trident sitting on the far bed as you stared at it.

Clearing your throat, you brought your attention away from the trident and have him a small smile. “No, thank you. Water’s fine.”

He nodded. “Smart choice,” he gave you a quick wink that made your heart flutter before taking the seat beside you.

“So, how are we going to kill these mermaids? They swim pretty deep, deeper than humanly possible,” Sam spoke, looking up from the old book he’d also picked up from the museum.

Dean shrugged, “so, we’ll have to be bait. Wait for them to come to us,” he replied matter of factly.

You gaped at the pair of them. “That’s a ridiculous plan,” you snapped, before you could even stop yourself, “They’ll kill you before you even blink.”

Dean raised his eyebrow at you, concern etching his features at your sudden reaction. “We’ll have the trident, Y/N. It’s toxic to all mermaids, right?” You could tell he was trying to reassure you, but it definitely wasn’t having the desired effect.

Even with the trident, there was no guarantee that the pair of them wouldn’t fall under the spell of the mermaids songs. One false move and both the Winchesters would be dead.

“And what about their song? Their voices that lure men to their death,” you argued.

“Well, we’re just gonna have to wear earphones and blare some AC/DC,” he quipped casually.

“This isn’t a joke!”

Frustration and anger were radiating through you by that point. You got to your feet and stormed out of the room, slamming the door behind you, not wanting to hear anymore about how they wanted to face the mermaids.

> __**‘There’s nothing left to say now,  
>  There’s nothing left to say now,   
> I’m giving up, giving up, hey, hey, giving up now  
> I’m giving up, giving up, hey, hey, giving up now,**   
>    
> 

You had your arms wrapped across your chest to try and shield yourself from the cool winds outside, sitting on a verge of grass just outside the motel. You gazed up at the sky, the moon shining brightly above you. You never could get over how stunning the sky looked at night, it didn’t matter if you were in sea or on land, it always amazed you.

“Y/N,” Dean’s voice pulled you out of you thoughts as he appeared beside you, covering your shoulders with one of his jackets. Another one of his gestures that made you heart warm inside. **  
**

“Thank you,” you murmured as he came and sat down beside you.

“Thanks for helping out with all this. We couldn’t have found the Trident without you,” Dean spoke, his eyes watching yours intently.

You looked back at him, trying to hide the guilt you were feeling. “Please be careful out there.”

A small smile crossed his lips. “Careful is my middle name.”

Rolling your eyes, you gave him a short look, “I’m being serious. Mermaids can be heartless creatures when they want to be,” the words had more personal meaning than you wanted to let on, which he obviously picked up on.

“How do you know so much about these creatures?”

You swallowed the lump in your throat and got to your feet, handing him back the jacket as he stood up with you, a curious look on his face.

“I told you, I’m a professor,” you replied. “I should really get going,” you made your way back to the motel, but before you could reach the door a strong hand grabbed onto your arm.

Dean looked like he wanted to say something and you were terrified that he was close to working out what you really were. Leaning forward, you pressed your lips against his in a gentle kiss, completely losing yourself in the feel of his soft, plump lips against yours. The embrace was a hundred times better than you’d been imagining since you first set eyes on him.

You pulled away after the all too quick moment, suddenly regretting your choice of actions as he looked back at you, stunned.

“I’m- I’m sorry, I-”

His hands grabbing onto your waist as he pulled you into a fevered kiss stopped your half way through your sentence. This man was completely blowing your mind and making you question everything, about why you’d come here in the first place and about returning to the sea.

You were in a complete haze of pleasure and happiness as he lead you to his car, the two of you quickly getting lost in each other, a tangle of bodies moving and writhing against each other. He brought feelings you never even thought you’d ever experience with a human, or anyone for that matter. **  
**

By the time the sun rose the next morning, Dean was still sleeping peacefully with you lying in his arms at the back of the Impala. You wanted nothing more than to stay with him forever, but you couldn’t.

* * *

> __**‘Below my soul, I feel an engine  
>  Collapsing as it sees the pain  
> If I could only shut it out,  
> **

 

Sam and Dean had left that morning to the beach to follow out on their plan to find the mermaids and take them out. Dean had promised he’d meet you back at the motel once they were done, that he’d take you for the night. It hurt your heart to lie to him, to smile and say you were looking forward to it before you kissed him goodbye.

Once they had left, you hitched yourself a ride to the beach, rushing down the sand just in time to see the pair of them in a hired boat, making their way from the docks.

 

You tore the necklace from around your neck and threw it down on the sand without a second thought. People were shouting at you as you ran down the docks and dived into the water, your clothes discarded as you went. The moment the water hit you, you already felt your whole body changing. An excruciating shooting pain suddenly rushed through you, your feet and legs both aching madly before transforming into a long, blue tail which helped you swim through the depths of the water, quickly making your way to the boat.

All the events after were a terrifying haze as you saw Dean get taken over board, Sam shouting his name, the golden Trident in his hands. You came above the surface, just as Sam was about to dive in after his brother, his eyes widening as he saw you.

“Y-Y/N.”

“Sam, I need the Trident.”

The second he gave it to you, you were back underwater- hastily trying to catch up with your relatives who were dragging Dean deeper into the water with each passing moment. The gold of the Trident was already burning your hands, the pain almost unbearable. But you had to get to Dean, you had to finish this.

> _**‘I’ve come too far to see the end now  
>  Even if my way is wrong  
> But I keep pushing on and on and on and on,**_ 

 

You fought off two of the mermaids, piercing the forked trident into their chest and watching as the life drained from their usual glowing eyes.

“You’ll burn for this,  _mare maleficus_ ,” one hissed, before letting go of Dean’s body.  “Will you kill me or save your human?”

Your grip on the trident tighten even more, the pain surging through your veins. You let out a scream before ramming the trident into her chest, letting it fall with her as she took her final breath and started falling into the deep. You swam faster and harder than you had ever done, relief flooding through you as you managed to grab hold of Dean in your arms.

Sam helped you hoist Dean back up into the boat the moment you reached the surface again. You watched in complete fear in the water as Sam tried relentlessly to wake Dean up, to bring him back. You both let out a relieved sigh as Dean coughed, his eyes flying open as he grabbed onto Sam’s arm.

 “I fucking hate mermaids,” he choked, Sam quickly helping him to sit up.

 

Dean’s eyes widened, his brows furrowed in confusion when he set eyes on you floating there, your long hair covering your chest. “Please tell me I’m hallucinating right now,” he murmured in a pained tone, and you couldn’t even meet his gaze. There was a prolonged silence before Dean spoke again,  **“I can’t believe I thought I could trust you.”**

Your heart sunk in your chest, his words hurting you more than you thought was possible. You winced and let out a cry as the burning pain raged through your body again. The toxic gold from holding the trident was definitely affecting you, maybe it was slower than usual reactions, but you were sure the outcome would be the same.

You looked back at Dean and Sam, tears in your eyes. “I’m truly sorry, for everything.” You turned and dived back in the opposite direction. Despite Dean desperately calling your name, you didn’t swim back, you couldn’t.

It wasn’t long before the pain completed overtook you, the last thing you saw was the beautiful blue of the sky before you fell into the pitch black.

* * *

Dean returned to the beach as often as he could in between cases. Sam had spotted your silver necklace when the two of them were making their way back to the impala that day you saved him. 

There was so much he didn’t understand, so much he wanted to ask you, to tell you.

He kept the necklace with him every day since, just in case by some miracle, you came back to the surface.

> __**‘There’s nothing left to say now,  
>  There’s nothing left to say now,   
> I’m giving up, giving up, hey, hey, giving up now  
> I’m giving up, giving up, hey, hey, giving up now.’**

  


**Notes for the Chapter:**

> {Sidenote: mare maleficus means sea witch in latin.}


End file.
